LAUSR

The indiscriminate use of chemical fertilizers has led to adverse environmental impacts and poor crop quality and accelerates the depletion of mineral reserves used for fertilizer production. Microbes are vital in soil nutrient cycling, and some effectively enhance soil nutrient supply and reduce chemical fertilizer usage. Biocontrol bacterium Lysobacter enzymogenes LE16 can produce various hydrolases against plant pathogens to mineralize soil organics via enzyme production. Therefore, the enzyme production, soil organic P and N mineralization, and crop agronomic performances induced by L. enzymogenes LE16 were investigated by pure culture, soil incubation, and greenhouse pot experiments. L. enzymogenes LE16 can hydrolyze lecithin and protein and convert them to inorganic P and NH4+-N. Similarly, available P and N increased as this bacterium was inoculated and grown in the tested soil. In the greenhouse pot experiment, phosphomonoesterase and protease produced by L. enzymogenes LE16 inoculant effectively mineralized soil organic P and N and enhanced soil available nutrients, thereby improving the nutrient uptake, fertilizer utilization rate, and agronomic efficiency of lettuce and pepper seedlings. Bacterial inoculation increased the lettuce yield by 6.43–11.30% and pepper fruit yield by 43.82–70.32%, even with less chemical fertilizer application. Therefore, L. enzymogenes LE16 can hydrolyze lecithin and protein in pure cultures, and mineralize organic P and N in soils, thus improving crop yield and quality and reducing chemical fertilizer application via the production of phosphomonoesterase and protease. L. enzymogenes LE16 shows potential for sustainable agriculture beyond plant protection.